#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/wait.h>
int main()
{
  printf("this is a process!,pid:%d\n",getpid()); 
  printf("exec begin... \n");
  execl("/usr/bin/ls","ls","-a","-l",NULL);
  printf("exec end... \n");
  
  return 0;
}
